In many manufacturing processes it is necessary to treat a workpiece with a liquid and then dry the workpiece. For example, during the manufacturing of magnetic disks, one typically performs the following manufacturing steps:
1. First a nickel-phosphorus layer is plated onto an aluminum substrate;
2. The nickel-phosphorus layer is polished and textured;
3. The substrate is cleaned, rinsed and dried;
4. A series of layers are sputtered onto the substrate, e.g., an underlayer such as sputtered NiP or Cr, a magnetic cobalt alloy, and a protective hydrogenated carbon overcoat.
Immediately prior to sputtering, the substrate is cleaned and then dried. It is extremely important that when the substrate is dried, there are no impurities left on its surface.
A well known drying technique relies upon hot de-ionized (DI) water to rinse and promote drying of the disk. By way of the hot DI water, the liquid on the wafer evaporates faster and more efficient than standard room temperature DI water. However, hot water often introduces stains on the disk, and also promotes build-up of bacterial and other particles. Another limitation is water is often expensive to heat, and hot DI water is also an aggressive solvent. As an aggressive solvent, it often deteriorates equipment and facilities, thereby increasing maintenance operation costs. One object of our invention is to overcome this problem.
Also, during the process of lifting the workpiece from the DI water, a holder arm is always in contact with the disk. This leaves the possibility that there will be a contamination or drying mark at the point where the disk is held during drying. Fung et al (U.S. Pat. No. 6,216,709 E1) addresses this problem by using a two stage lifting process, whereby a drying portion of the disk is not held by a wet holding mechanism. In spite of this, there could be embellishments where the holding mechanism attaches to the disk. Another object of our invention is to overcome this problem.